2008 Accord Rear Defrost Not Working [Confirmed Fix]
#11
10-12-2013 | 01:43 PM
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See the attached pic., which is an excerpt from a January 2012 Honda Service News article. There have been other Honda articles which stated a different time to do the reset with the jumper wire and a slightly different procedure; such as 15 minutes without having to turn the ignition ON vs. 10 minutes and turning the ignition ON while doing the reset.
#13
10-12-2013 | 02:54 PM
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If swapping the relay doesn't change anything, you could try backprobing the green wire at Connector C304, while the connector is plugged in, to check for voltage. If there is voltage at C304, then the problem would be further back toward the rear of the car.
You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.
You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.
#14
10-13-2013 | 11:23 AM
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If swapping the relay doesn't change anything, you could try backprobing the green wire at Connector C304, while the connector is plugged in, to check for voltage. If there is voltage at C304, then the problem would be further back toward the rear of the car.
You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.
You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.
#15
10-13-2013 | 12:06 PM
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Just to make sure, this is voltage at the Grn wire and not the Light green wires at the C304 connector, with the key off? One Light green wire is for the brake pedal position circuit and another Light green wire is for the EVAP system.
If it is the Grn wire, it may be due to the multiplex system still energizing the relay for a short period of time after the key is turned off. Wait a while, and don't turn the ignition to ON, then test for voltage at the Grn wire and see if you still see voltage at the Grn wire.
The rear window defogger relay is a normally open type of relay. As stated in part in my Post #6, "When the defogger switch, climate control unit is pressed, the defog signal is sent to the driver's MICU. The driver's MICU provides the ground to the rear defogger relay, which energizes the relay. Battery voltage is then allowed through the relay to the rear window defogger." So, if the driver's MICU does not provide the ground to the relay, battery voltage is not suppose to go through to the Grn wire. The relay is normally open going to the Grn wire. Only when the driver's MICU supplies ground to the relay, does the relay close to allow the battery voltage to go through.
Regardless, if you're getting voltage to the Grn wire at C304, then the problem is further down the circuit toward the rear.
If it is the Grn wire, it may be due to the multiplex system still energizing the relay for a short period of time after the key is turned off. Wait a while, and don't turn the ignition to ON, then test for voltage at the Grn wire and see if you still see voltage at the Grn wire.
The rear window defogger relay is a normally open type of relay. As stated in part in my Post #6, "When the defogger switch, climate control unit is pressed, the defog signal is sent to the driver's MICU. The driver's MICU provides the ground to the rear defogger relay, which energizes the relay. Battery voltage is then allowed through the relay to the rear window defogger." So, if the driver's MICU does not provide the ground to the relay, battery voltage is not suppose to go through to the Grn wire. The relay is normally open going to the Grn wire. Only when the driver's MICU supplies ground to the relay, does the relay close to allow the battery voltage to go through.
Regardless, if you're getting voltage to the Grn wire at C304, then the problem is further down the circuit toward the rear.
Last edited by redbull-1; 11-03-2013 at 10:03 AM.
#16
10-13-2013 | 01:52 PM
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If swapping the relay doesn't change anything, you could try backprobing the green wire at Connector C304, while the connector is plugged in, to check for voltage. If there is voltage at C304, then the problem would be further back toward the rear of the car.
You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.
You can use something like a T pin, available at Walmart, etc., and backprobe. These pictures are just to give a picture of the concept of backprobing without piercing any wires.
#17
10-13-2013 | 02:49 PM
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If there was 12 volt at the Grn wire with rear defog on, relay is good even without having to swap the relays.
The problem is further down the circuit toward the rear. It can even be a loose ground connection at Ground G801 behind the right C pilllar trim panel area (this has been known to occur).
The problem is further down the circuit toward the rear. It can even be a loose ground connection at Ground G801 behind the right C pilllar trim panel area (this has been known to occur).
#18
10-13-2013 | 02:55 PM
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Newest Of Newbies
Joined: Dec 2007
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If there was 12 volt at the Grn wire with rear defog on, relay is good even without having to swap the relays.
The problem is further down the circuit toward the rear. It can even be a loose ground connection at Ground G801 behind the right C pilllar trim panel area (this has been known to occur).
The problem is further down the circuit toward the rear. It can even be a loose ground connection at Ground G801 behind the right C pilllar trim panel area (this has been known to occur).
